Operation

Loading the rifle

(a) Single round: to load a single round, pull the operating rod all the way to the rear. While holding the muzzle below horizontal, place a round in the chamber and seat it with the thumb. With the knife edge of the right hand against the operating rod handle, force the operating rod slightly to the rear. Push down on the follower assembly with the thumb of the right hand and allow the bolt to ride forward. (Caution! Restrain the forward movement of the bolt with the knife edge of the right hand against the operating rod handle.) Remove the thumb from the follower assembly and release the operating rod handle, allowing the operating rod to go all the way forward.

(b) Full clip: hold the rifle at the balance with the left hand and pull the operating rod handle all the way to the rear. Place the butt of the rifle on the ground or against the thigh. With the right hand, place a full clip on the top of the follower assembly. Place the thumb on the center of the top round in the clip and press straight down into the receiver until it catches. Swing the right hand up and to the right to clear the bolt in its forward movement. Note that the operating rod is not held to the rear during loading since there is no danger of it going forward as long as pressure is maintained on the top round in the clip. If the bolt does not fully close and lock, tap soundly with the heel of the right hand against the operating rod handle.

(c) Partly filled clip: hold the rifle in the same manner prescribed for a full clip. With the operating rod all the way to the rear, place an empty clip into the receiver. Place the first round into the clip and on the follower, to the left of the follower slide. Press the second round into the clip, exerting a downward, turning motion until the round maps into place. Load the remaining rounds in the same manner. With the knife edge of the right hand against the operating rod handle, force the operating rod handle slightly to the rear. Push down on the top round with the right thumb, allowing the bolt to start the top round forward. Remove the right hand and allow the operating rod to go forward.

Functioning of the Rifle

a. The trigger must be pulled to fire each round. When the last round is fired, the empty clip is automatically ejected and the bolt remains to tile rear.

b. Each time a round is loaded and tired, many parts inside the rifle work in a given order. This is known as tile cycle of operation. This cycle is similar in all small arms. A knowledge of what happens inside the rifle during this cycle of operation will help the soldier understand the cause of and remedy for various stoppages.

c. The cycle of operation is broken down into eight steps. These steps are listed below, together with a brief description of what actually occurs inside the rifle during each step. Assume that. a full or partially filled clip has been loaded into the rifle and that the first round has been fired and the bolt, is in its rearmost position.

(1) Feeding. Feeding takes place when a round is moved into the path of the bolt. This is done by the follower assembly exerting an upward pressure on the bottom round in the clip. The follower assembly is continuously forced up by the pressure of the operating rod spring through the follower rod and follower arm.

(2) Chambering. Chambering occurs when a round is moved into the chamber. This takes place as the bolt goes forward under pressure of the expanding operating rod spring, picking up the top round in the clip and driving it forward into the chamber. Chambering is complete when file extractor snaps into the extracting groove on the cartridge case and the ejector is forced into the face of the bolt.

(3) Locking. Locking is complete when the bolt is fully closed. This prevents the loss of gas pressure until the bullet has left the muzzle. The bolt is locked by the rear camming surface in the recess in the hump of the operating rod, forcing the operating lug of the bolt down. This engages the locking lugs on the bolt with their recesses in the receiver.

(4) Firing. Firing occurs when the firing pin strikes the primer. As the trigger is pulled tile trigger tugs are disengaged from the hamnmr hooks and the hammer is released. The hammer moves forward under the pressure of the hammer spring and strikes the tang of the firing pin, driving the firing pin against the primer and firing the round.

(5) Unlocking. Unlocking occurs after the firing of the round. As the bullet is forced through the barrel by the expanding gas, a small portion of the gas escapes through the gas port into the gas cylinder forcing the operating rod to the rear. The camming surface inside the recess in the hump of the operating rod forces the operating lug d the bolt upward, disengaging the locking lugs from their recesses in the receiver. The bolt is thus unlocked and ready to be moved to the rear.

(6) Extracting. Extracting is pulling the empty cartridge case from the chamber. The extractor, which is engaged with the extracting groove on the cartridge case, withdraws the empty case as the bolt moves to the rear.

(7) Ejecting. Ejecting is throwing the empty case from the rifle. As the bolt moves to the rear, withdrawing the case from the chamber, the round is held in place by the chamber walls. When the mouth of the empty case clears the chamber, it is ejected up and to the right by the expanding ejector spring and ejector.

 
(8) Cocking. Cocking occurs when the hammer is forced into the proper position for firing the next round. This happens as the bolt continues to the rear. The rear end of the bolt forces the hammer back and rides over it. The hammer is caught by the sear if the trigger is still held to the rear, but it is caught by the trigger lugs if trigger pressure has been released. (see picture above)